Roasting Your Own Coffee Begins with Green Beans and a Skillet

How to make your home brew even more “home brew”-ish? What about roasting your own beans? Coffee Stout or Witte anyone?- PGA

Picture of roasting beans, Doug Beghtel, The Oregonian

Written by Grant Butler for The Oregonian

Portland loves its DIY culture, with all its craft fairs, knitting classes and home-brewing get-togethers. Portland also loves coffee, with temples of java dotting the map like tattoos on the arms of baristas.

That these passions have come together seems inevitable. Instead of just heading to a nearby coffee shop for an artfully poured latte, more people are learning what it takes to make coffee at home that’s vastly superior to what people used to drink. And there’s a fast-growing trend of people roasting their own coffee beans.

“It puts you in touch with what makes good coffee good,” says Trevin Miller, who just opened Mr. Green Beans, a new North Mississippi Avenue store that sells green coffee beans and everything you need to roast coffee at home. “Whether it’s something you want to continue or just want to try, it gives you a better understanding of what it takes to make great coffee.”

I’ve always been a hands-on coffee geek. In college, friends teased me for having four different coffee-brewing systems (percolator, automatic drip, moka pot and a pour-over cone) while not having basic kitchen items like cookie sheets or a soup pot. The percolator went to a yard sale a long time ago, replaced by an elaborate espresso machine that steams milk perfectly and produces shots with a delicious layer of crema on the top. And recently, I’ve been obsessing over cold-brewed coffee, which added yet another gadget to an already stuffed pantry.

When a friend told me about Mr. Green Beans, I knew I had to check it out — even if I didn’t have the money (or the counter space) to invest in a fancy roasting system. As it turns out, you don’t need a bunch of equipment; Miller walked me through how to roast beans using a heavy-duty skillet as well as an old popcorn popper.

The first step is figuring out what type of beans to buy. This being Portland, where food and politics often co-mingle, Miller opted to stock only fairly traded beans.

“We stick with socially and environmentally aware coffee growers,” he says. “We do the homework ahead of time to make sure they all meet some sort of regulation, whether it’s fair trade or one of the organic certifiers, like Rainforest Alliance or Smithsonian Songbird (Smithsonian Migratory Bird Center). We try to stick solely with those coffees.”

Another consideration when choosing beans is how you plan to roast them. If you want to do it in a skillet, you need peaberry beans, which are round and will roast more evenly as they are agitated in the pan. With a hot-air popper, you can use regular beans, which are sometimes referred to as flatberry beans for the distinct look — flat on one side and rounded on the other. Since I planned to try both methods, I picked up a bag of green peaberry beans from Bolivia and a bag of regular beans from Guatemala.

Once you get your beans home, you want to store them the way you’d keep rice or beans, keeping them in a cool, dry place out of direct sunlight. Because green beans are stable, you can keep them six months or longer before roasting without worrying about spoilage.

Getting started, and playing with fire

Before roasting my first batch, I read the step-by-step instructions in Mr. Green Beans’ free home-roasting guide and in the beautiful new book “The Art and Craft of Coffee,” by Kevin Sinnott. In both places one word jumped out: fire.

Because coffee roasts at temperatures between 400 and 500 degrees, the beans are likely to put off a lot of smoke, so a good ventilation system is a must. And there’s a slim chance the beans could ignite, so having a fire extinguisher nearby is essential — just in case.

With a little bit of trepidation — Rule No. 1: Don’t set the FOOD day test kitchen on fire! — I poured  1/2 cup of green peaberry beans into a hot skillet and started agitating the pan to keep them in constant motion. In less than a minute, the beans started changing color, first turning a light shade of yellow, then beginning to brown. After about four minutes, the beans turned a light brown and were starting to emit a loud cracking sound, known as “first crack.” This is caused by the expansion of the beans as they roast and start to shed their chaff.

And boy, do these beans shed. The chaff is super light and goes flying through the air as the skillet is agitated. Be warned that after roasting is complete, there’s going to be some serious cleanup.

At the six-minute mark, the beans turned medium brown and started to send up wisps of smoke. Remembering Rule No. 1, I took the skillet off the stove and dumped the beans into a metal colander, which I shook to air-cool the beans as quickly as possible. While shaking the beans, it started raining chaff as the spent skins that had stayed in the skillet found their way through the colander holes. I moved this process over the sink, since I’d already made a mess with the chaff-covered stove.

After the beans had cooled, I let them rest for a few hours while they emitted CO2 , which is a natural byproduct of the roasting process. Then they were transferred to a glass jar, ready for brewing the next morning.

The coffee brewed from that first batch of beans was relatively characterless, reminiscent of the sort of coffee you might drink in a church fellowship hall or at a civic function. The flavor was fresh and inoffensive, but I longed for a more forceful cup. So it was back to the test kitchen for round two.

This time, I roasted the beans two minutes longer and cranked up the stove’s fan as the smoke poured out. The beans emitted the softer-sounding “second crack” and turned a rich, dark brown, which the pros call “full city roast.” The coffee brewed from these beans had a lot more oomph. Definitely a step up from the first go-around.

Next up: Mastering using a hot-air popcorn popper to roast beans. You need a popper with vents on the side of the popping chamber, not a mesh screen across the bottom. The reason, Miller says, is safety.

“Oil and chaff from the beans can go through that filter onto the heating element and could catch your popcorn popper on fire,” he says. “I’ve never heard of that happening, and a lot of people use these poppers and love them. But the potential for danger is there.”

Armed with the right kind of popper, I poured in  1/2 cup of Guatemalan beans, replaced the lid and turned the popper on. The beans began whirring around the chamber, and within two to three minutes, the beans began to crack, and chaff began floating out of the popping shoot into a large bowl I’d positioned below. This cut down on the smoke significantly, keeping the test kitchen from being enveloped in another acrid cloud.

By the 12-minute mark, the beans had gone through their second crack, were dark brown and began to have a light spotting of oil on their surface, characteristic of the Vienna Roast, which is just shy of the dark roasts of espresso and French roasts.

The next morning, those Guatemalan beans went into the grinder, and my kitchen was filled with the best coffee bean aroma I’d ever encountered. And the brewed cup was heavenly. All from a popcorn popper — amazing!

Passionate home roaster turns pro

Catching home-roasting fever can take everyday coffee fans to unusual places. Just ask Justin Johnson, who went from an avid DIY coffee roaster to a professional at Water Avenue Coffee Co., an industrial eastside micro-roaster that’s one of the hottest new arrivals on Portland’s coffee scene.

Johnson says he’s from a family with coffee in its blood. “We’re knee-deep in it. My uncle is a coffee farmer in Puerto Rico, and we always had espresso, even in the early ’80s.” He started roasting beans at home in the mid-’90s.

“I’d never had such a good cup of coffee before,” he says, “though if I were to go back now and taste that coffee, I’d probably say, ‘Oh, God!'”

His first batches were all about experimentation.

“I was obsessed with it,” he says. “I kept smoking the house up. Luckily, I had a good hood over my stove and an understanding girlfriend at the time.”

Since then he’s tried more than 20 elaborate home-roasting systems and currently uses a Gene Cafe roaster from Korea, which gives him far greater control over how dark the beans get than with a more primitive home method. Mr. Green Beans carries plenty of home-roasting systems, which run anywhere from $100 to about $900, including that Gene Cafe that Johnson uses. The price tag: just under a cool $500.

I’m too new at this to make that sort of splurge.

No worries, says Miller, who remains fond of the simplest roasting methods.

“We never made the leap from a popcorn popper to a bigger roaster until we opened the store,” Miller says. “We always stuck with the popcorn popper method. It’s fun and inexpensive, and sometimes produces incredible coffee.”

Grant Butler

Finding green coffee beans

Online: There are many online sources for green coffee beans and home-roasting supplies. Among the best are and

How to roast your own coffee

To roast your own coffee at home, all you need is a heavy skillet or a hot-air popcorn popper, plus a good ventilation system to handle the smoke. Try to roast your coffee during daylight hours or under bright lighting so you can see the changing color of the beans.

Safety note: Approach coffee roasting with the same level of caution you would use when frying food and never leave the roaster unattended. Because of the high heat, there’s a slim chance the beans could ignite. If using the skillet method and the beans catch fire, smother them with a tight-fitting lid or fire extinguisher. If using an electric hot-air popper, unplug it before dousing it with a fire extinguisher or water.

(Notes for picture below: by Doug Beghtel, for The Oregonian. Though a white ceramic skillet allows you to easily judge the darkness of the beans, it’s not essential. Just be sure to have good lighting and watch the beans carefully.)

Skillet method

1. For best results, be sure to use green peaberry coffee beans, which are round and will roast more evenly in a skillet than split coffee beans.

2. Heat the skillet over high heat for 2 to 3 minutes, then add  1/2 cup green coffee beans. Using a hot pad or an oven mitt, agitate skillet constantly to keep beans from burning. Switch arms if you start to get tired!

3. Listen for the first crack of the beans, which comes 3 to 5 minutes into the roasting process. This will sound similar to popcorn popping and is caused by the beans expanding. At this point, the coffee is light brown (called an American roast) and is drinkable. Stop here if you like a lighter coffee style, or continue roasting until beans are medium-brown (“city” roast), darker brown with tiny droplets of oil on their surface (“full city” roast), or almost black with lots of oil on the surface (French roast). At some point, you’ll hear a second, softer crack, caused by the beans’ cell structure fracturing. You may want to try several small batches to determine the roast that is right for you.

4. When the beans reach the desired roast, immediately dump them into a large metal colander. Using hot pads, agitate the beans so they cool quickly, 3 to 5 minutes. It’s a good idea to do this over a sink, since the colander will rain chaff.

5. When the beans are cool, place them in glass jars and leave open for at least four hours while the beans emit CO2 . The jars can then be sealed, and the beans are ready to use.

(Notes for picture below: by Doug Beghtel, for The Oregonian. If you hate single-purpose appliances, now you have an excuse to buy a hot-air popcorn popper, which does a fine job of roasting coffee and contains the messy chaff.)

Hot-air popcorn-popper method

1. Make sure your popcorn popper is the type with vents on the sides of the popping chamber. Poppers with mesh screens on the bottom are prone to catch fire and are thus unsuitable for roasting coffee beans.

2. Place 1/2 cup green coffee beans in the popper. Place lid securely on roaster, and position a large bowl under the chute to catch the chaff, which will be forced out by hot air during the roasting process.

3. Turn the popper on and follow Steps 3 to 5 for the skillet method.

— Grant Butler

Thinking about trying your hand at coffee roasting? Consider these pros and cons.


You don’t have to buy a bunch of fancy equipment to get started. All you need is a heavy-duty skillet or that old hot-air popcorn popper left over from your dorm days.
Because you’re doing the labor, you’re saving money. A pound of green Guatemalan beans runs just $5, about half the price of a pound of preroasted beans.

Coffee doesn’t get any fresher than this. You can brew your first batch right away (though letting the coffee rest for a few hours is better). No more studying bags for “roasted on” or “best by” dates.

You love doing things from scratch, whether it’s making your own pie crust or pickles. How can you resist roasting your own coffee beans?


Once you catch coffee-roasting fever, you may find yourself lusting after elaborate home roasters, which can run anywhere from around $100 to $900.
Those savings disappear if you burn a batch and have to toss scorched beans into the compost bin.

Coffee doesn’t get any messier than this. Because beans roast at around 500 degrees, there’s going to be smoke, so you need a good ventilation system. And roasting produces lots of messy chaff, which has a knack for finding its way into every nook and cranny in your kitchen.

If you’re already irked by the task of grinding coffee beans, do you seriously think you’ll find time to roast them, too?

— Grant Butler

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